I thought I would share this book from my library today before it is gone. This is Farm Gas Engines and Tractors, by Fred Jones, 1938.
Lots of great information here. I am donating this book to our High School shop class today and wanted to share it first. Our shop class has won several awards with their vintage restored tractors, and are building a library of old farm related technology. I will try to get pics of the tractors to share.
Enjoy.